The website ad used an image of a girl wearing a short skirt and white underwear, bending over to touch the ground and photographed from behind. The Instagram post showed a girl wearing a skirt and top leaning into a car also photographed from behind from a low angle. In both versions the girl’s buttocks were visible.

The ASA received two complaints that challenged whether the ads were "offensive and irresponsible" because they were "overtly sexual and inappropriate for a skirt advertised as school-wear".

American Apparel claimed its approach was not graphic, explicit or pornographic but designed to show a range of different images of people who were natural. It said its models were happy, relaxed and confident in expression and pose and not portrayed in a vulnerable, negative or exploitative manner.

The company added that it drew a strong distinction between print or other conventional media and web and social images. It claimed American Apparel is well known for using provocative images and that people who browse its social media feeds and website had "opted in".

However, the ASA upheld the complaint stating that in its consideration, the way in which the model was posed in both images meant the focus was on her buttocks and groin rather than on the skirt.

It also said that it was likely that viewers would understand the model was, or was intended to appear to be, a schoolgirl and considered the ads had the effect of inappropriately sexualising school-age girls.

The ASA found the images were gratuitous and objectified women and so were sexist and likely to cause serious and widespread offence irrespective of whether consumers had "opted in" to American Apparel's marketing communications.

The ASA ruled that the ads must not appear again in their current form. The watchdog also warned American Apparel to ensure its future advertising was prepared with a sense of responsibility to consumers and to society and that it contained nothing that was likely to cause serious or widespread offence.